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    <h1>egg-watcher</h1>
    <p>File watcher plugin for egg</p>
<p><a href="https://npmjs.org/package/egg-watcher" target="_blank" rel="noopener"><img src="https://img.shields.io/npm/v/egg-watcher.svg?style=flat-square" alt="NPM version"></a>
<a href="https://travis-ci.org/eggjs/egg-watcher" target="_blank" rel="noopener"><img src="https://img.shields.io/travis/eggjs/egg-watcher.svg?style=flat-square" alt="build status"></a>
<a href="https://codecov.io/github/eggjs/egg-watcher?branch=master" target="_blank" rel="noopener"><img src="https://codecov.io/github/eggjs/egg-watcher/coverage.svg?branch=master" alt="Test coverage"></a>
<a href="https://david-dm.org/eggjs/egg-watcher" target="_blank" rel="noopener"><img src="https://img.shields.io/david/eggjs/egg-watcher.svg?style=flat-square" alt="David deps"></a>
<a href="https://snyk.io/test/npm/egg-watcher" target="_blank" rel="noopener"><img src="https://snyk.io/test/npm/egg-watcher/badge.svg?style=flat-square" alt="Known Vulnerabilities"></a>
<a href="https://npmjs.org/package/egg-watcher" target="_blank" rel="noopener"><img src="https://img.shields.io/npm/dm/egg-watcher.svg?style=flat-square" alt="npm download"></a></p>
<h2 id="usage"><a class="markdown-anchor" href="#usage">#</a> Usage</h2>
<p>In worker process:</p>
<h3 id="appwatcherwatchpath-listener"><a class="markdown-anchor" href="#appwatcherwatchpath-listener">#</a> app.watcher.watch(path, listener)</h3>
<p>Start watching file(s).</p>
<ul>
<li>path(String|Array): file path(s)</li>
<li>listener(Function): file change callback</li>
</ul>
<h3 id="appwatcherunwatchpath-listener"><a class="markdown-anchor" href="#appwatcherunwatchpath-listener">#</a> app.watcher.unwatch(path[, listener])</h3>
<p>Stop watching file(s).</p>
<ul>
<li>path(String|Array): file path(s)</li>
<li>listener(Function): file change callback</li>
</ul>
<p>In agent process:</p>
<h3 id="agentwatcherwatchpath-listener"><a class="markdown-anchor" href="#agentwatcherwatchpath-listener">#</a> agent.watcher.watch(path, listener)</h3>
<p>Start watching file(s).</p>
<ul>
<li>path(String|Array): file path(s)</li>
<li>listener(Function): file change callback</li>
</ul>
<h3 id="agentwatcherunwatchpath-listener"><a class="markdown-anchor" href="#agentwatcherunwatchpath-listener">#</a> agent.watcher.unwatch(path[, listener])</h3>
<p>Stop watching file(s).</p>
<ul>
<li>path(String|Array): file path(s)</li>
<li>listener(Function): file change callback</li>
</ul>
<h2 id="watching-mode"><a class="markdown-anchor" href="#watching-mode">#</a> Watching mode</h2>
<h3 id="development-mode"><a class="markdown-anchor" href="#development-mode">#</a> <code>development</code> Mode</h3>
<p>There's a built-in <a href="https://github.com/eggjs/egg-watcher/blob/master/lib/event-sources/development.js" target="_blank" rel="noopener">development mode</a> which works in local(env is <code>local</code>). Once files on disk is modified it will emit a <code>change</code> event immediately.</p>
<h3 id="customize-watching-mode"><a class="markdown-anchor" href="#customize-watching-mode">#</a> Customize Watching Mode</h3>
<p>Say we want to build a custom event source plugin (package name: <code>egg-watcher-custom</code>, eggPlugin.name: <code>watcherCustom</code>).</p>
<p>Firstly define our custom event source like this:</p>
<figure class="highlight js"><table><tr><td class="code"><pre><span class="line"><span class="comment">// &#123;plugin_root&#125;/lib/custom_event_source.js</span></span><br><span class="line"><span class="keyword">const</span> Base = <span class="built_in">require</span>(<span class="string">'sdk-base'</span>);</span><br><span class="line"><span class="class"><span class="keyword">class</span> <span class="title">CustomEventSource</span> <span class="keyword">extends</span> <span class="title">Base</span> </span>&#123;</span><br><span class="line">  <span class="comment">// `opts` comes from app.config[$&#123;eventSourceName&#125;]</span></span><br><span class="line">  <span class="comment">// `eventSourceName` will be registered later in</span></span><br><span class="line">  <span class="comment">// `config.watcher.eventSources` as the key shown below</span></span><br><span class="line">  <span class="keyword">constructor</span>(opts) &#123;</span><br><span class="line">    <span class="keyword">super</span>(opts);</span><br><span class="line">    <span class="keyword">this</span>.ready(<span class="literal">true</span>);</span><br><span class="line">  &#125;</span><br><span class="line"></span><br><span class="line">  watch(path) &#123;</span><br><span class="line">    <span class="comment">// replace this with your desired way of watching,</span></span><br><span class="line">    <span class="comment">// when aware of any change, emit a `change` event</span></span><br><span class="line">    <span class="comment">// with an info object containing `path` property</span></span><br><span class="line">    <span class="comment">// specifying the changed directory or file.</span></span><br><span class="line">    <span class="keyword">this</span>._h = setInterval(<span class="function"><span class="params">()</span> =&gt;</span> &#123;</span><br><span class="line">      <span class="keyword">this</span>.emit(<span class="string">'change'</span>, &#123; path &#125;);</span><br><span class="line">    &#125;, <span class="number">1000</span>);</span><br><span class="line">  &#125;</span><br><span class="line"></span><br><span class="line">  unwatch() &#123;</span><br><span class="line">    <span class="comment">// replace this with your implementation</span></span><br><span class="line">    <span class="keyword">if</span> (<span class="keyword">this</span>._h) &#123;</span><br><span class="line">      clearInterval(<span class="keyword">this</span>._h);</span><br><span class="line">    &#125;</span><br><span class="line">  &#125;</span><br><span class="line">&#125;</span><br><span class="line"></span><br><span class="line"><span class="built_in">module</span>.exports = CustomEventSource;</span><br></pre></td></tr></table></figure>
<p>Event source implementations varies according to your running environment. When working with vagrant, docker, samba or such other non-standard way of development, you should use a different watch API specific to what you are working with.</p>
<p>Then add your custom event source to config:</p>
<figure class="highlight js"><table><tr><td class="code"><pre><span class="line"><span class="comment">// config.default.js</span></span><br><span class="line">exports.watcher = &#123;</span><br><span class="line">  eventSources: &#123;</span><br><span class="line">    custom: <span class="built_in">require</span>(<span class="string">'../lib/custom_event_source'</span>),</span><br><span class="line">  &#125;,</span><br><span class="line">&#125;;</span><br></pre></td></tr></table></figure>
<p>Choose to use your custom watching mode in your desired env.</p>
<figure class="highlight js"><table><tr><td class="code"><pre><span class="line"><span class="comment">// config.$&#123;env&#125;.js</span></span><br><span class="line">exports.watcher = &#123;</span><br><span class="line">  type: <span class="string">'custom'</span>,</span><br><span class="line">&#125;;</span><br><span class="line"></span><br><span class="line"><span class="comment">// this will pass to your CustomEventSource constructor as opts</span></span><br><span class="line">exports.watcherCustom = &#123;</span><br><span class="line">  <span class="comment">// foo: 'bar',</span></span><br><span class="line">&#125;;</span><br></pre></td></tr></table></figure>
<p>If possible, plugins named like <code>egg-watcher-${customName}</code>(<code>egg-watcher-vagrant</code> eg.) are recommended.</p>
<h2 id="questions-suggestions"><a class="markdown-anchor" href="#questions-suggestions">#</a> Questions &amp; Suggestions</h2>
<p>Please open an issue <a href="https://github.com/eggjs/egg/issues" target="_blank" rel="noopener">here</a>.</p>
<h2 id="license"><a class="markdown-anchor" href="#license">#</a> License</h2>
<p><a href="https://github.com/eggjs/egg-watcher/blob/master/LICENSE" target="_blank" rel="noopener">MIT</a></p>

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